I want to ask why was this change enacted. EasyList still only adheres to filters supported by Adblock Plus and the previous tagline seems more appropriate. Please clear my apprehensions about this new change.

There's nothing that I can think off in the rules that deal with ABP only not counting AA as that's an ABP only feature. Everything else has directions for AdBlock, ABP and uBO. Unless you're seeing something I'm not I think we're pretty well covered.